The paper aims to assess hydrodynamic features of liquid-liquid flows in serpentine microchannels to control mixing and mass transfer. Segmented or plug flow of the oil-water system in serpentine microchannels with different curvatures is studied. The novelty of the topic consists in the use of multiple bends of high curvature (width to curvature radius ratio β = 1) in conjunction with the low viscosity ratio of phases (λ = 0.001). Plug acceleration/deceleration in straight parts and bends depends on the channel curvature and leads to a drastic change in the plug length. Plug elongation is more pronounced for higher channel curvature and is found to be a linear function on the capillary number. Plug rupture is discovered in the microchannel with β = 1. Flow structure in both the oil slugs and aqueous plugs is visualized using laser-induced fluorescence and particle tracking velocimetry techniques. Qualitatively different flow patterns in oil slugs are revealed depending on the bend curvature. In the aqueous plugs additional vortex appears due to curvature influence and intensifies for higher curvature. Optimal conditions for efficient mixing and mass transfer in the plug flow regime are stated.

本文旨在评估蛇形微通道中液-液流动的流体动力学特征，以控制混合和传质。研究了不同曲率的蛇形微通道中油水系统的分段或塞流。该主题的新颖性在于使用高曲率的多个弯曲（宽度与曲率半径之比β= 1）以及相的低粘度比（λ= 0.001）。笔直零件和弯曲处的塞子加速/减速取决于通道曲率，并导致塞子长度急剧变化。对于较高的通道曲率，塞子伸长更为明显，并且发现其是毛细管数的线性函数。在β= 1的微通道中发现了塞子破裂。使用激光诱导的荧光和粒子跟踪测速技术，可以看到油团和含水塞中的流动结构。根据弯曲曲率，可以发现油团中流质的定性不同。在水塞中，由于曲率影响而出现了额外的涡流，并为更高的曲率而加剧。阐述了在活塞流状态下有效混合和传质的最佳条件。